# File lib/facter/util/virtual.rb, line 178
  def self.docker?
    path = Pathname.new('/proc/1/cgroup')
    return false unless path.readable?
    begin
      in_docker = path.readlines.any? {|l| l.split(":")[2].to_s.include? '/docker' }
    rescue Errno::EPERM => exc
      # This can fail under OpenVZ, just like in .lxc?
      return false
    end
    return true if in_docker
    return false
  end